U.S. patent application number 10/795974 was filed with the patent office on 2004-12-02 for electronic apparatus with communication device.
Invention is credited to Homma, Tooru, Yata, Koichi.
Application Number | 20040240418 10/795974 |
Document ID | / |
Family ID | 32767915 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040240418 |
Kind Code |
A1 |
Yata, Koichi ; et
al. |
December 2, 2004 |
Electronic apparatus with communication device
Abstract
An electronic apparatus executes communication with an external
device. The electronic apparatus includes an encoder that encodes
source data to generate transmission data, a communication device
that transmits the transmission data generated by the encoder to
the external device, a unit that determines the quality with which
the source data is to be transmitted, in accordance with the type
of the source data, and a unit that controls the encoder to vary an
amount of the generated transmission data on the basis of the
determined quality.
Inventors: |
Yata, Koichi; (Hanno-shi,
JP) ; Homma, Tooru; (Kawaguchi-shi, JP) |
Correspondence
Address: |
Finnegan, Henderson, Farabow
Garrett & Dunner, L.L.P.
1300 I Street, N.W.
Washington
DC
20005-3315
US
|
Family ID: |
32767915 |
Appl. No.: |
10/795974 |
Filed: |
March 10, 2004 |
Current U.S.
Class: |
370/338 ;
370/352; 704/E19.019; 709/231 |
Current CPC
Class: |
G10L 19/0208 20130101;
H04L 1/0014 20130101 |
Class at
Publication: |
370/338 ;
370/352; 709/231 |
International
Class: |
G06F 015/16 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 11, 2003 |
JP |
2003-065410 |
Claims
What is claimed is:
1. An electronic apparatus comprising: an encoder that encodes
source data to generate transmission data; a communication device
that transmits the transmission data generated by the encoder to an
external device; means for determining a quality with which the
source data is to be transmitted, in accordance with a type of the
source data; and means for controlling the encoder to vary an
amount of the generated transmission data on the basis of the
determined quality.
2. The electronic apparatus according to claim 1, wherein the
controlling means includes means for setting in the encoder a value
of sampling frequency, which is to be used in the encoding of the
source data, in accordance with the determined quality.
3. The electronic apparatus according to claim 1, wherein the
controlling means includes means for setting in the encoder a kind
of an encoding scheme, which is to be used in the encoding of the
source data, in accordance with the determined quality.
4. The electronic apparatus according to claim 1, wherein the
controlling means includes means for setting in the encoder a kind
of an encoding scheme, which is to be used in the encoding of the
source data, and a value of sampling frequency, which is to be used
in the encoding of the source data, in accordance with the
determined quality.
5. The electronic apparatus according to claim 1, further
comprising a plurality of input devices capable of inputting data,
wherein the quality determining means includes means for detecting
the type of the source data by determining from which of the input
devices the source data is input.
6. The electronic apparatus according to claim 1, wherein the
communication device includes a wireless communication device that
executes communication with the external device via a wireless
network, and the quality determining means includes: means for
detecting a number of devices connected to the wireless
communication device via the wireless network; and means for
determining the quality with which the source data is to be
transmitted, on the basis of the detected number of devices and the
type of the source data.
7. The electronic apparatus according to claim 1, wherein the
communication device includes a wireless communication device that
executes communication with the external device via a wireless
network, the source data includes audio data, the electronic
apparatus further includes means for determining whether a device
that transmits image data is connected to the wireless
communication device via the wireless network, and the quality
determining means includes means for determining, when the device
that transmits image data is connected to the wireless
communication device, the quality with which the source data is to
be transmitted, such that transmission of the image data is
executed with priority over transmission of the source data.
8. A program that is stored in a computer-readable medium and
controls communication for transmitting transmission data, which is
generated by encoding source data, from a computer to an external
device, comprising: causing the computer to determine a quality
with which the source data is to be transmitted, in accordance with
a type of the source data; and causing the computer to execute a
process of controlling an operation of the encoding to vary an
amount of the generated transmission data on the basis of the
determined quality.
9. The program according to claim 8, wherein said causing the
computer to execute the process of controlling the operation of the
encoding includes causing the computer to execute a process of
determining a value of sampling frequency, which is to be used in
the encoding process, in accordance with the determined
quality.
10. The program according to claim 8, wherein said causing the
computer to execute the process of controlling the operation of the
encoding includes causing the computer to a process of determining
a kind of an encoding scheme, which is to be used in the encoding
process, in accordance with the determined quality.
11. The program according to claim 8, wherein said causing the
computer to execute the process of controlling the operation of the
encoding includes causing the computer to execute a process of
determining a kind of an encoding scheme, which is to be used in
the encoding process, and a value of sampling frequency, which is
to be used in the encoding process, in accordance with the
determined quality.
12. The program according to claim 8, wherein said causing the
computer to determine the quality includes causing the computer to
execute a process of detecting the type of the source data by
determining from which of a plurality of input devices of the
computer the source data is input.
13. The program according to claim 8, wherein the computer is
connected to the external device via a wireless network, and said
causing the computer to determine the quality includes: causing the
computer to execute a process of detecting a number of devices
connected to the computer via the wireless network; and causing the
computer to execute a process of determining the quality with which
the source data is to be transmitted, on the basis of the detected
number of devices and the type of the source data.
14. The program according to claim 8, wherein the computer is
connected to the external device via a wireless network, the source
data includes audio data, the program further includes causing the
computer to execute a process of determining whether a device that
transmits image data is connected to the computer via the wireless
network, and said causing the computer to determine the quality
includes causing the computer to execute a process of determining,
when the device that transmits image data is connected to the
wireless communication device, the quality with which the source
data is to be transmitted, such that transmission of the image data
is executed with priority over transmission of the source data.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from prior Japanese Patent Application No. 2003-65410,
filed Mar. 11, 2003, the entire contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an electronic apparatus
capable of transmitting content such as music to an external
device, and also relates to a program for controlling communication
of the electronic apparatus.
[0004] 2. Description of the Related Art
[0005] In recent years, attention has been paid to Bluetooth.TM. as
a wireless communication technology. Bluetooth.TM. is a low-cost,
low-power-consumption, short-range wireless communication
technology suitable for mobile devices. Bluetooth.TM. is used for
mutual connection of various mobile information devices owned by
individual users. The devices are wirelessly connected and,
compared to conventional connection by wire, the devices can be
connected more freely, simply and easily.
[0006] Jpn. Pat. Appln. KOKAI Publication No. 2002-112383 discloses
a system wherein music data is transmitted from an electronic
device such as a music player to headphones by means of radio
signals.
[0007] In order to reproduce music with high quality by headphones,
it is necessary to enhance the quality relating to transmission of
music data from the electronic apparatus to the headphones.
[0008] Bluetooth.TM. is capable of not only one-to-one
communication, but also one-to-many communication. However, the
wireless communication bandwidth of Bluetooth.TM. is narrow. If
music data is always transmitted with high quality, almost all the
available wireless communication bandwidth is occupied by the
transmission of music data. In this case, such a problem arises
that wireless communication between a device other than the
headphones and the electronic apparatus is disrupted.
[0009] In addition, in a case where the quality of music source
itself is low, even if the music source is transmitted with high
quality using a wide communication bandwidth, an excess
communication bandwidth is uselessly occupied without enhancing the
quality of music reproduced from the headphones.
BRIEF SUMMARY OF THE INVENTION
[0010] According to an embodiment of the present invention, there
is provided an electronic apparatus comprising: an encoder that
encodes source data to generate transmission data; a communication
device that transmits the transmission data generated by the
encoder to an external device; means for determining a quality with
which the source data is to be transmitted, in accordance with a
type of the source data; and means for controlling the encoder to
vary an amount of the generated transmission data on the basis of
the determined quality.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0011] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate embodiments of
the invention, and together with the general description given
above and the detailed description of the embodiments given below,
serve to explain the principles of the invention.
[0012] FIG. 1 shows an external appearance of a computer according
to an embodiment of the present invention;
[0013] FIG. 2 is a block diagram showing the system configuration
of the computer of FIG. 1;
[0014] FIG. 3 shows an example of a quality definition table for
use in the computer of FIG. 1;
[0015] FIG. 4 shows an example of an operation screen of an audio
player that is used in the computer of FIG. 1;
[0016] FIG. 5 is a block diagram showing the software scheme of the
computer of FIG. 1;
[0017] FIG. 6 is a block diagram showing a system configuration of
a headset that is wirelessly connected to the computer of FIG.
1;
[0018] FIG. 7 illustrates a connection establishing process that is
executed by the computer of FIG. 1;
[0019] FIG. 8 is a flow chart illustrating the procedure of a
transmission quality determination process that is executed by the
computer of FIG. 1; and
[0020] FIG. 9 is a flow chart illustrating the procedure of a
connection control process that is executed by the computer of FIG.
1.
DETAILED DESCRIPTION OF THE INVENTION
[0021] An embodiment of the present invention will now be described
with reference to the accompanying drawings.
[0022] FIG. 1 shows the external appearance of an electronic
apparatus 10 according to an embodiment of the invention. The
electronic apparatus 10 is configured to be able to transmit a
stream of content data such as music or voice to an external device
20 by radio signals. The electronic apparatus 10 is realized by,
e.g. a notebook personal computer, and the external device 20 is
realized by, e.g. a wireless headset.
[0023] The personal computer 10 is a portable information
processing apparatus that can be driven by a battery. The personal
computer 10 comprises a computer main body 11 and a display unit
12. A display device composed of an LCD (Liquid Crystal Display)
121 is built in the display unit 12. The LCD 121 is positioned at a
substantially central area of the display unit 12.
[0024] The display unit 12 is attached to be rotatable between an
open position and a closed position relative to the computer main
body 11. The computer main body 11 has a thin box-shaped casing. A
keyboard 13, a power button 14 for powering on/off the computer 10,
a touch pad (pointing device) 15, etc. are disposed on the upper
surface of the computer main body 11.
[0025] A wireless communication device is built in the computer
main body 11. The wireless communication device enables the
computer 10 to perform communication with the headset 20. The
wireless communication device is configured to execute wireless
communication according to Bluetooth.TM. standards.
[0026] In Bluetooth.TM., SS-FH (spread spectrum-frequency hopping)
is used. 79 frequency channels are assigned to a frequency band of
2.4 GHz at intervals of 1 MHz. Frequency channels that are used are
switched in units of a packet according to a hopping sequence
("frequency hopping").
[0027] Wireless communication by Bluetooth.TM. standards is
realized by a master-slave configuration, and the master manages
the hopping sequence. Using the same hopping pattern, a wireless
network called "piconet" can be formed between one master and seven
or less slaves.
[0028] The computer 10 can perform, using the wireless network,
communication with a mouse 30 and a camera 40 as well as with the
headset 20.
[0029] A connection control program, which is a program for
controlling wireless communication with the headset 20, is
installed in the computer 10. The connection control program
controls transmission of audio data such as music from the computer
10 to the headset 20.
[0030] In Bluetooth.TM., Advanced Audio Distribution Profile (A2DP)
is specified as a profile relating to transmission of audio data.
A2DP is a function for transmitting audio data such as music with
high quality. In A2DP, an asynchronous data channel called ACL
(Asynchronous Connectionless) is utilized.
[0031] The connection control program controls the wireless
communication device, thereby executing a procedure for
transmitting audio data to the headset 20 using A2DP. Not only
various audio data stored as music data files in the computer 10
but also various audio data received from the Internet 60 via a
modem 50 can be used as source data of audio that is to be
reproduced by the headset 20.
[0032] The connection control program has a function of dynamically
varying the quality, with which source data is to be transmitted,
in accordance with the type of the source data that is to be
reproduced by the headset 20. The source data is converted to
transmission data having a predetermined transmission data format,
and the transmission data is transmitted as an audio stream from
the computer 10 to the headset 20. The transmission data is
generated by encoding the source data by an encoder provided in the
computer 10.
[0033] The quality relating to the transmission of source data
becomes higher as the amount of transmission data generated from
the source data increases. The connection control program controls
the operation of the encoder, thereby varying the quality relating
to the transmission of source data. The generated transmission data
is sent from the computer 10 to headset 20 as an audio stream.
[0034] The headset 20 is an output device that reproduces an audio
stream of music, voice, etc., which is sent from the computer 10 by
radio, and generates sound corresponding to the audio data of the
audio stream. In the headset 20, the audio stream sent from the
computer 10 is decoded and the decoded audio stream is
reproduced.
[0035] The headset has a microphone 205. A signal of voice of the
user, which is input from the microphone 25, is transmitted by
radio to the computer 10.
[0036] The headset 20 is configured to be wearable on the head of
the user. The headset 20, as shown in FIG. 1, comprises a head arm
201, and two ear pads 202 and 203 provided at both ends of the head
arm 201. Each ear pad 202, 203 incorporates a speaker. Each ear pad
202, 203 functions as a speaker unit.
[0037] In the state in which the headset 20 is worn on the head of
the user, the two ear pads 202 and 203 cover the right and left
ears of the user. One end of a microphone arm 204 is attached to
the pad 202, and the other end thereof is provided with the
microphone 205.
[0038] Next, the system configuration of the computer 10 is
described referring to FIG. 2.
[0039] The computer 10, as shown in FIG. 2, comprises a CPU 101, a
host bridge 102, a main memory 103, a display controller 104, a
system controller 105, a hard disk drive (HDD) 106, a CD/DVD drive
107, a wireless communication device 108, a sound controller 110,
an audio amplifier 111, a speaker 112, a modem 113, a LAN
controller 114, a BIOS-ROM 115, and an embedded controller/keyboard
controller IC (EC/KBC) 116.
[0040] The CPU 101 is a processor provided to control the
operations of the computer 10. The CPU 101 executes an operating
system (OS) 301 and various application/utility programs, which are
loaded in the main memory 103 from the hard disk drive (HDD) 106.
The CPU 101 also executes a BIOS (Basic Input/Output System) stored
in the BIOS-ROM 115.
[0041] In the computer 10, the aforementioned connection control
program 302 is pre-installed as one of the utility programs. In
addition, an audio player 303 is installed as an application
program for reproducing audio data.
[0042] Using a quality definition table 300 as shown in FIG. 3, the
connection control program 302 determines an optimal transmission
quality that is suited to source data to be reproduced. The quality
definition table 300 prestores definition information indicative of
whether high-quality transmission is necessary or not in
association with each type (S=1 to 5) of source data. In the
quality definition table 300 shown in FIG. 3, ".smallcircle."
designates source data requiring high-quality transmission, and "X"
designates source data requiring only low-quality transmission. The
value (S) is used as an index for searching the quality definition
table 300.
[0043] In the present embodiment, the type of source data is
classified according to the type of input device (disk drives and
Internet-connection communication devices) that inputs source data
to be reproduced by the headset 20.
[0044] Normally, audio data stored in storage media such as
CDs/DVDs is high-quality data that is specifically used for music,
which is sampled at a high sampling frequency. On the other hand,
the quality of audio data stored in the HDD is, in many cases, not
so high. Thus, the connection control program 302 classifies the
type of source data according to the type of disk drive in which
the source data to be reproduced by the headset 20 is stored.
[0045] In addition, in the case where audio data such as music
data, which is present on Web sites on the Internet 60, is used as
source data, the connection control program 302 classifies the type
of the source data (data requiring high-quality transmission or
data requiring only low-quality transmission) according to whether
the communication line for connection to the Internet 60 is a
broadband high-speed line or a narrowband low-speed line.
[0046] In this way, in accordance with the type of input device for
inputting source data, the optimal transmission quality for the
source data is determined.
[0047] In practice, in order to prevent adverse effect on
communication between the computer 10 and a device other than the
headset 20, the connection control program 302 determines the
quality with which source data is to be transmitted, taking into
account not only the type of the source data to be sent to the
headset 20, but also the number of devices (number of links)
currently wirelessly connected to the computer 10 and the
establishment/non-establishment of the link with the camera 40.
[0048] If high-quality transmission of audio data to the headset 20
is started in the state in which video data such as motion video is
being transmitted from the camera 40 to the computer 10, faults
such as halt of video data transmission or halt of audio data
transmission may occur. In the present embodiment, when the number
of links is relatively large or when the link between the camera 40
and computer 10 is established, the transmission quality of audio
data is set at a low level.
[0049] In FIG. 2, the host bridge 102 is a bridge device that
connects the local bus of the CPU 101 and the system controller
105. The host bridge 102 includes a memory controller that controls
access to the main memory 103. The display controller 104 controls
the LCD 121 that is used as a display monitor of the computer
10.
[0050] The system controller 105 controls each device on a PCI
(Peripheral Component Interconnect) bus 1 and each device on an ISA
(Industry Standard Architecture) bus 2. The system controller 105
includes an IDE (Integrated Drive Electronics) controller for
controlling the HDD 106 and CD/DVD drive 107. The system controller
105 also includes a USB (Universal Serial Bus) controller 200. The
wireless communication device 108 is connected to the USB
controller 200.
[0051] The wireless communication device 108 is a device for
executing wireless communication and includes a baseband unit and
an RF (Radio Frequency) unit. The RF unit performs
transmission/reception of a radio signal via an antenna (ANT) 109.
The wireless communication device 108 is configured to execute
wireless communication according to Bluetooth.TM. standards.
[0052] The sound controller 110 is a device for reproducing audio
data. An audio signal output from the sound controller 110 is
delivered to the speaker 112 via the audio amplifier (AMP) 111. The
speaker 112 produces the audio signal as sound. The modem 113 and
LAN controller 114 are wired communication devices capable of
communicating with the Internet 60. The modem 113 is used to
connect the computer 10 to the Internet 60 via a narrowband
low-speed communication line such as a telephone line. The LAN
controller 114 is used to connect the computer 10 to the Internet
60 via a broadband high-speed communication line such as an XDSL or
CATV. The LAN controller 114 is connected to the XDSL or CATV via
the modem 50 designed for the XDSL or CATV.
[0053] The embedded controller/keyboard controller IC (EC/KBC) 116
is a one-chip microcomputer in which an embedded controller for
power management and a keyboard controller for controlling the
keyboard (KB) 13 and touch pad 15 are integrated. The keyboard (KB)
13 and touch pad 15 are user interface units that can be operated
by the user. In addition, the embedded controller/keyboard
controller IC (EC/KBC) 116 has a function of powering on/off the
computer 10 in accordance with the operation of the power button 14
by the user.
[0054] FIG. 4 shows an example of an operation screen 70 that is
displayed on the LCD 121 by the audio player 303.
[0055] The operation screen 70 is a window that prompts the user to
select audio data to be reproduced. The operation screen 70
contains an [HDD] tab 71, a [CD/DVD] tab 72, an [INTERNET] tab 73,
and a [PLAY] button 75.
[0056] If the user clicks the [HDD] tab 71, a source data list 74
that presents audio data items stored in the HDD 106 is displayed.
The source data list 74 displays the song title, artist name, and
album title for each of audio data. The user can select audio data
to be reproduced, from the source data list 74. Similarly, when the
user clicks the [CD/DVD] tab 72, a source data list that presents
audio data items stored in the CD/DVD drive 107 is displayed. When
the user clicks the [INTERNET] tab 73, a source data list that
presents audio data items stored on a specific Web site on the
Internet 60 is displayed.
[0057] When the [PLAY] button 75 is clicked, the audio player 303
starts reproduction of audio data selected from the source data
list. The connection control program 302 cooperates with the audio
player 303 and executes a process for transmitting a stream of the
selected audio data to the headset 20 with a transmission quality
corresponding to the type of the selected audio data.
[0058] The scheme of software for controlling the wireless
communication device 108 is described referring to FIG. 5.
[0059] The wireless communication device 108 comprises a hardware
logic (baseband unit 504 and RF unit 505) and firmware for
controlling the hardware logic. The firmware includes a BUS driver
501, an HCI (Host Control Interface) driver 502, and an LMP (Link
Management Protocol) 503. The BUS driver 501 is a driver for
connecting the wireless communication device 108 to a bus such as a
USB. The HCI driver 502 is a driver for communication with the host
(computer 10) via the BUS driver 501. The LMP 503 is a driver for
controlling a physical wireless link.
[0060] As programs for controlling the wireless communication
device 108, protocol drivers 307 that constitute a protocol stack,
as well as the aforementioned connection control program 302, are
installed in the computer 10.
[0061] The protocol drivers 307 include an AV (audio/video)
protocol driver 401 for executing an A2DP function, an HCI driver
402 for executing communication with the wireless communication
device 108, and a BUS driver 403 for controlling the bus such as a
USB, to which the wireless communication device 108 is
connected.
[0062] The connection control program 302 controls the wireless
communication device 108 via the protocol drivers 307, thereby
controlling transmission of an audio data stream between the
headset 20 and computer 10. The connection control program 302 can
acquire, through the operating system (OS) 301 or audio player 303,
information indicative of the type of the input device for
inputting source data to be reproduced (i.e. the type of disk drive
in which the source data is stored, or the type of communication
device for receiving the source data from the Internet). The
connection control program 302 determines the transmission quality
of source data in accordance with the type of input device, by
referring to the quality definition table 300.
[0063] In the connection establishing process for streaming, the
connection control program 302 sets communication conditions
associated with the determined transmission quality in the computer
10 and headset 20 in accordance with the content of an environment
setting information file 306.
[0064] The setting of the communication conditions is executed
using predetermined parameter information associated with the
high-quality transmission and low-quality transmission. The
parameter information is information for controlling the data
amount of transmission data to be generated, and it includes
various parameter values such as the kind of CODEC
(COmpression/DECompression) to be applied to source data that is to
be transmitted, and the value of sampling frequency used in the
CODEC.
[0065] The parameter indicative of the kind of CODEC designates a
compression-encoding scheme by which the source data to be
transmitted is compressed and encoded. This parameter is set in an
encoder provided in the computer 10 and in a decoder provided in
the headset 20. The parameter indicative of the value of sampling
frequency designates a sampling frequency with which source data to
be transmitted should be sampled in the encoding of the source
data. This parameter, too, is set in the encoder provided in the
computer 10 and in the decoder provided in the headset 20.
[0066] The environment setting information file 306 prestores
parameter information corresponding to the communication conditions
for realizing high-quality transmission (e.g. the kind of
compression-encoding scheme applied to source data, and the value
of sampling frequency), and parameter information corresponding to
the communication conditions for realizing low-quality transmission
(e.g. the kind of compression-encoding scheme applied to source
data, and the value of sampling frequency).
[0067] In the high-quality streaming, for example, low-compression
SBC (Subband Codec) is used. SBC is a compression-encoding/decoding
scheme for music data, and a relatively large amount of arithmetic
operations are needed for the processing of SBC. SBC, however,
realizes sound reproduction with a sufficiently high quality on the
receiving side.
[0068] In the low-quality streaming, SBC or .mu.-law is used. The
value of sampling frequency used in SBC in the low-quality
streaming is lower than the value of sampling frequency used in SBC
in the high-quality streaming.
[0069] As has been described above, the parameter values such as
the kind of CODEC and the sampling frequency are varied according
to the quality with which the source data is to be transmitted. As
a result, the data amount of transmission data (the bit rate of
transmission data), which is generated from the source data, is
changed. Accordingly, the wireless communication bandwidth required
for transmitting source data is varied in accordance with the type
of the source data.
[0070] A network driver 308 is a driver program for controlling the
modem 113 or LAN controller 114 under control of the OS 301. Audio
data, which is transferred by streaming from a Web site on the
Internet 60, is sent to the audio player 303 via the network driver
308 and OS 301. A CD/DVD driver 309 is a driver program for
controlling the CD/DVD drive 107 under control of the OS 301. Audio
data, which is read out of the CD/DVD drive 107, is sent to the
audio player 303 via the CD/DVD driver 309 and OS 301. An HDD
driver 310 is a driver program for controlling the HDD 106 under
control of the OS 301. Audio data, which is read out of the HDD
106, is sent to the audio player 303 via the HDD driver 310 and OS
301.
[0071] Audio data reproduced by the audio player 303 is delivered
to a first sound driver 304 or a second sound driver 305 via the OS
301. The first sound driver 304 is a driver for controlling the
sound controller 110. The first sound driver 304 is used to produce
sound from the built-in speaker 112 via the sound controller 110.
The second sound driver 305 is a driver for transmitting audio data
to the wireless communication device 108 via the protocol drivers
307.
[0072] The connection control program 302 loads the second sound
driver 305 in the main memory 103, thereby to send audio data to
the headset 20 by radio. The second sound driver 305 has a higher
priority than the first sound driver 304.
[0073] After the second sound driver 305 is loaded, the second
sound driver 305, in place of the first sound driver 304, is used
by the OS 301. Accordingly, audio data reproduced by the audio
player 303 is sent to the second sound driver 305 as source data to
be reproduced by the headset 20.
[0074] The second sound driver 305 has a CODEC 600 associated with
both SBC and .mu.-law. The CODEC 600 includes an encoder, which
encodes source data using SBC or .mu.-law and generates
transmission data, and a decoder that decodes transmission data
using SBC and .mu.-law.
[0075] The second sound driver 305 encodes source data (audio data)
to be transmitted, using a compression-encoding scheme designated
by the connection control program 302. The value of sampling
frequency used in the compression-encoding process is also
designated by the connection control program 302. By the encoding
process, the source data is converted to transmission data.
[0076] Referring now to FIG. 6, the system configuration of the
headset 20 is described.
[0077] The headset 20, as shown in FIG. 6, comprises a wireless
communication device 701, a system controller 702, an audio
reproducing unit 703, and an audio input unit 704.
[0078] The system controller 702 is a processor provided to control
the operations of the headset 20. The system controller 702
controls the wireless communication device 701, audio reproducing
unit 703 and audio input unit 704. The system controller 702
includes a CODEC 801 associated with both SBC and .mu.-law. The
CODEC 801 includes a decoder that decodes transmission data
received as an audio stream, using SBC and .mu.-law, and an encoder
that encodes an input voice signal from the microphone 205, using
SBC and .mu.-law, and generates transmission data.
[0079] The wireless communication device 701, like the wireless
communication device 108 of computer 10, executes wireless
communication on the basis of a procedure according to
Bluetooth.TM. standards.
[0080] The audio reproducing unit 703 executes a data reproduction
process for streaming reproduction. That is, in this process, while
receiving an audio data stream sent from the computer 10 via the
wireless communication device 701 and system controller 702, the
audio reproducing unit 703 converts the audio data stream to an
electric signal that can be output as sound from a speaker 206
built in each pad 202, 203. The audio input unit 704 converts an
analog voice signal input from the microphone 205 to a digital
signal, and delivers it to the system controller 702.
[0081] FIG. 7 illustrates a connection establishing process that is
executed by the connection control program 302.
[0082] The connection control program 302 controls the wireless
communication device 108 of the computer 10, thereby starting the
connection establishing process. In the connection establishing
process, a procedure is executed for establishing a channel
(transport channel) for transmitting audio data such as music from
the computer 10 to the headset 20.
[0083] In the connection establishing process, the connection
control program 302 sets communication conditions, which correspond
to the transmission quality determined according to the type of
source data, in both the computer 10 and headset 20 that are to
function as stream end points of the transport channel. In this
case, in practice, the connection control program 302 detects the
capability of the headset 20 by executing negotiation with the
headset 20. Based on the detected capability of the headset 20 and
the communication conditions corresponding to the determined
transmission quality, the connection control program 302 determines
optimal communication conditions that are to be actually used in
the data streaming between the computer 10 and headset 20, and sets
the optimal communication conditions in the CODEC 600 of computer
10 and the CODEC 801 of headset 20.
[0084] The computer 10 functions as a source device for
transmitting audio data via the established transport channel. The
headset 20 functions as a sink device for receiving audio data that
is transmitted via the established transport channel. Following the
connection establishing process, a process (streaming) for
transmitting audio data from the computer 10 to the headset 20 is
started.
[0085] The procedure of a transmission quality determination
process that is executed by the connection control program 302 will
now be described with reference to a flow chart of FIG. 8.
[0086] The connection control program 302 executes the following
transmission quality determination, for example, when the [PLAY]
button 75 on the operation screen.70 shown in FIG. 4 is
clicked.
[0087] To start with, the connection control program 302 determines
whether the camera 40 is wirelessly connected to the computer 10,
that is, whether a link between the wireless communication device
108 and camera 40 is established (step S101). If the camera 40 is
wirelessly connected to the computer 10 (YES in step S101), the
connection control program 302 determines a low quality as the
quality for transmission of audio data to be reproduced, which is
selected on the operation screen 70 (step S102). Thus, the
transmission of image data such as moving image between the camera
40 and the computer 10 is executed with priority over transmission
of the audio data from the computer 10 to the headset 20.
[0088] If the camera 40 is not wirelessly connected to the computer
10 (NO in step S101), the connection control program 302 determines
whether the number of devices (number of links) currently
wirelessly connected to the computer 10 is a predetermined number
(n) or more (step S103). If the number of links is n or more, the
connection control program 302 determines a low quality as the
quality for transmission of audio data to be reproduced (step
S102). The default value of n is, e.g. 3. The value n can be varied
by the user.
[0089] If the number of links is less than n, the connection
control program 302 detects the type of audio data to be
reproduced, that is, the type of input device used for inputting
audio data to be reproduced.
[0090] Specifically, the connection control program 302 determines
whether the audio data to be reproduced is audio data stored in the
HDD 106 (step S104). If the audio data to be reproduced is the data
stored in the HDD 106 (YES in step S104), the connection control
program 302 sets S=1 (step S105). If the audio data to be
reproduced is not data stored in the HDD 106 (NO in step S104), the
connection control program 302 determines whether the audio data to
be reproduced is audio data stored in the CD/DVD drive 107 (step
S106).
[0091] If the audio data to be reproduced is the audio data stored
in the CD/DVD drive 107 (YES in step S106), the connection control
program 302 sets S=2 (step S107). If the audio data to be
reproduced is not data stored in the CD/DVD drive 107 (NO in step
S106), the connection control program 302 determines whether the
audio data to be reproduced is audio data stored on a Web site on
the Internet 60 (step S108). If the audio data to be reproduced is
audio data stored on the Web site on the Internet 60, that is,
audio data transferred from the Internet 60 (YES in step S108), the
connection control program 302 asks the OS 301 whether the
communication device currently used for connection to the Internet
60 is the modem 113 or LAN controller 114, thereby determining
whether the communication line currently used for connection to the
Internet 60 is a high-speed line (step S109). If the communication
line is the high-speed line (YES in step S109), the connection
control program 302 sets S=3 (step S111). If the communication line
is a low-speed line (NO in step S109), the connection control
program 302 sets S=4 (step S110).
[0092] If the audio data to be reproduced is not data transferred
from the Internet 60 (NO in step S108), the connection control
program 302 sets S=5 (step S112).
[0093] Then, the connection control program 302 searches the
quality definition table 300 using the set value S as an index,
thereby determining the quality with which the audio data to be
reproduced is to be transmitted (step S113).
[0094] Next, a connection control process that is executed by the
connection control program 302 is described with reference to a
flow chart of FIG. 9.
[0095] After determining the quality with which the
to-be-reproduced audio data is to be transmitted, the connection
control program 302 executes the following connection control
process in order to establish the transport channel for
transmitting audio data from the computer 10 to the headset 20 with
the determined quality.
[0096] In order to set a communication environment for wirelessly
transmitting audio data to the headset 20 with the determined
quality, the connection control program 302 starts the connection
establishing process. In the connection establishing process, the
connection control program 302 sets communication conditions (the
kind of CODEC and the value of sampling frequency), which
correspond to the quality determined by the process of FIG. 8, in
the computer 10 and headset 20 that are to function as stream end
points of the transfer channel (step S201). Specifically, the
parameter information including the kind of CODEC and the value of
sampling frequency is set in the CODEC 600 of the computer 10 and
in the CODEC 801 of the headset 20. The setting of the
communication conditions is effected via a control channel that is
established between the computer 10 and headset 20.
[0097] The role of the sink device is assigned to the remote
device, that is, the headset 20. The role of the source device is
assigned to the local device, that is, the computer 10. The
processing in step S201 establishes the transport channel for
transmitting audio data such as music from the computer 10 to the
headset 20 with the determined quality.
[0098] Then, the connection control program 302 loads the second
sound driver 305 (step S202), and informs the headset 20 of the
start of streaming, thus executing a streaming process (step S203).
In step S203, transmission data (audio stream) is generated from
source data such as music or voice by the CODEC 600, and the audio
stream is wirelessly transmitted from the computer 10 to the
headset 20.
[0099] As has been described above, according to the present
embodiment, the transmission quality, with which source data that
is to be reproduced by the headset 20 is to be transmitted, is
automatically optimized according to the kind of the source data.
Therefore, the source data to be reproduced, such as music, can
efficiently be wirelessly transmitted, without occupying the
entirety of the wireless communication bandwidth of Bluetooth.TM..
Moreover, the quality for transmitting the source data is
determined by also taking into account the number of links and the
connection/disconnection of the camera 40. Thus, the source data to
be reproduced, such as music, can be transmitted to the headset 20,
without adversely affecting wireless communication between the
computer 10 and a device other than the headset 20.
[0100] All the quality determination process and connection control
process are realized by the computer program. Therefore, the same
advantages as with the present embodiment can easily be obtained by
simply installing the computer program in a computer with a
wireless communication function, using a computer-readable storage
medium storing this computer program.
[0101] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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